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North America. Now, P. Cardui is found in India, but 
P. Atalanta is not , but instead of it we find there is a species 
which is termed P. Indica vel Callirhoe, of which I exhibit 
a specimen. This insect appears to be an intermediate form 
between Cardui and Atalanta. In the upper side of Indica , 
the insect is substantially Atalanta, while the lower portions 
of the wings bear a resemblance to Cardui. In the under 
side, the upper portions of the upper wings are similar to 
Atalanta, and the lower to Cardui, and in the lower wings 
the upper portion resembles Cardui, and the lower Atalanta. 
It would be extremely interesting to try whether a cross 
could be obtained resembling Indica, by breeding Cardui 
with Atalanta for a few generations. In the free state the 
Cardui and Atalanta are generally found together, yet no 
intermediate is discoverable co-existent. P. Cardui is a 
curious insect in the manner of its appearances. Some years 
it is so exceedingly abundant as to become a pest, while 
probably the next year hardly a specimen is to be found in 
that locality. It is to be found near the sea coast, and in 
all places up to the summits of Ben Lawers and Snowdon. 
Though much has been done towards elucidating many 
problems of geographical distribution, there is still much to 
be explained. For instance, in the Isle of Man there are 16 
of the 64 British species of butterflies. They none of them 
present any difference from the English forms except one, the 
Vanena Urticse, small tortoise shell. When I was in the 
Isle of Man, in 1879, I to;.k a remarkably small specimen of 
that insect, and on showing it to Mr. Edwin Birchall, he 
informed me that this small variety is the only form of 
Y. Urticae taken in the Island, and very kindly presented 
me with a series. 
In conclusion, I must express my best thanks to Mr. 
Melvill, who most kindly placed his large collection at my 
disposal to select any insects that I wished, for the purpose 
of comparison with the Shetland and Hebrides forms. 
